Highly selective and sensitive sensor based on an organic electrochemical transistor for the detection of ascorbic acid

- A novel MIP-based OECT sensor was designed for the first time to detect and identify AA.
- The MIP-OECT sensor exhibited a sensitivity of 75.3 μA channel current change per decade.
- The detection platform showed high selectivity for AA detection.

In this study, an organic electrochemical transistor sensor (OECT) with a molecularly imprinted polymer (MIP)-modified gate electrode was prepared for the detection of ascorbic acid (AA). The combination of the amplification function of an OECT and the selective specificity of MIPs afforded a highly sensitive, selective OECT sensor. Cyclic voltammetry and electrochemical impedance spectroscopy measurements were carried out to monitor the stepwise fabrication of the modified electrodes and the adsorption capacity of the MIP/Au electrodes. Atomic force microscopy was employed for examining the surface morphology of the electrodes. Important detection parameters, pH and detection temperature were optimized. With the change in the relative concentration of AA from 1 μM to 100 μM, the MIP-OECT sensor exhibited a low detection limit of 10 nM (S/N > 3) and a sensitivity of 75.3 μA channel current change per decade under optimal conditions. In addition, the MIP-OECT sensor exhibited excellent specific recognition ability to AA, which prevented the interference from other structurally similar compounds (e.g., aspartic acid, glucose, uric acid, glycine, glutathione, H2O2), and common metal ions (K+, Na+, Ca2+, Mg2+, and Fe2+). In addition, a series of vitamin C beverages were analyzed to demonstrate the feasibility of the MIP-OECT sensor. Using the proposed principle, several other sensors with improved performance can be constructed via the modification of organic electrochemical transistors with appropriate MIP films.

The combination between the amplified function of OECT and selective specificity of MIP yielded an OECT sensor with high sensitivity and selectivity. The MIP-OECT sensor exhibited a sensitivity of 75.3 μA channel current change per decade, and excellent specific recognition ability to AA which could avoid the interference of other structurally similar compounds and common metal ions.191